I believe a mastiff is bigger. Bull Mastiffs are a cross between a mastiff and a bulldog. The Mastiff is the taller of the two but the Bullmastiff is more compact and muscled. The correct spelling is...
That's up to the people involved with it, but realistically, anything over 8 inches is kind of pointless. I've come across a few 12 inch ones and while fun to play with, they tend to be too much of a...